Appointed by Joseph Pulitzer as Paris correspondent for the New York World, Steed joined The Times in 1896 as a foreign correspondent, working briefly out of Berlin before transferring successively to Rome ( from 1897 until 1902) and then Vienna (1902–13). In 1914 he moved to London to take over as foreign editor of The Times. During his time in Vienna he acquired a deep contempt for Austria-Hungary.[1] An anti-Semite and a Germanophobe, in an editorial published in The Times on 31 July 1914, Steed labelled efforts to stop the impending war as "a dirty German-Jewish international financial attempt to bully us into advocating neutrality".[2] From 22 July 1914 on, Steed in close agreement with The Times' proprietor, Lord Northcliffe, took a very bellicose line and in editorials written on 29 and 31 July, Steed urged that the British Empire should enter the coming war.[3]

Seen as a leading expert on Eastern Europe, Steed's views had much influence with decision-makers such as high level bureaucrats and Cabinet politicians in the First World War and its aftermath. During the war, Steed befriended anti-Habsburg émigrés such as Edvard Beneš, Ante Trumbić, Tomáš Masaryk and Roman Dmowski and advised the British government to seek the liquidation of Austria-Hungary as a war aim. In particular, Steed was a very strong advocate of uniting all of the South Slavic peoples such as the Croats, the Serbs, the Slovenes, etc. into a federation to be called Yugoslavia. The British Ambassador to Italy claimed in a diplomatic dispatch that Steed's fondness for the Yugoslav concept derived from a relationship he maintained for a number of years "filially I believe rather maritally" with a Slavic woman from the Balkans.[1] In October 1918, Steed met with the Serbian Prime Minister Nikola Pašić to gain his support for the Yugoslav concept; Steed was deeply angered when he learned that Pašić saw the new state as merely as extension of greater Serbia and had no intention of sharing power with the Croats or the Slovenes.[1] Steed charged Pašić with being a new "sultan" and severed his friendship with Paśić.[1]

When the editor of The Times, Geoffrey Dawson, resigned from his post in February 1919, Steed was Northcliffe's first choice to succeed him. Steed had worked closely with Northcliffe during the war, becoming an adviser to him on foreign affairs.Steed was forced to contend with Northcliffe throughout most of his tenure as editor, as the press baron retained considerable control over the affairs of the newspaper.

After the war, Steed strongly disapproved of the Bolshevik regime in Russia. In an editorial written in another Northcliffe paper, the Daily Mail on 28 March 1919, Steed accused the British Prime Minister David Lloyd George, whom Steed detested of betraying the White Russians because of a plot by "international Jewish financiers" and the Germans to help the Bolsheviks stay in power.[4]

In 1920, Steed endorsed the notorious anti-Semitic forgery The Protocols of the Learned Elders of Zion as genuine in an editorial in The Times. In the same editorial, Steed blamed the Jews for World War I, the Bolshevik regime and called Jews the greatest threat to the British Empire. However, in 1921, when The Times's Constantinople correspondent proved that The Protocols were a forgery, Steed retracted his endorsement of The Protocols.

Despite being Northcliffe's personal choice for the editorship, by 1922 the press baron was increasingly frustrated with Steed's failure to return The Times to profitability. After Northcliffe's death in August 1922, the paper's new owners, John Jacob Astor and John Walter, dismissed Steed on 24 October and brought back Dawson as editor.

In 1923 Steed became editor of Review of Reviews (1923–30), the journal established by William Thomas Stead in 1890. In the early 1930s, he was one of the first English speakers to express alarm about the new German Chancellor Adolf Hitler. In 1934, he caused sensation with an article claiming to have evidence of secret German experiments in airborne biological warfare.[5] This alarmed the British government sufficiently to start stockpiling vaccines,[6] although a retrospective analysis by the epidemiologist Martin Hugh-Jones has suggested that Steed's evidence could not have amounted to much.[7] On the title page of his 1934 work, Hitler Whence and Whither?, Steed is described as a lecturer in Central European History at King's College London.